Gravar-mail: 2-Hydr­oxy-16-[(E)-4-hydr­oxy-3-methoxy­benzyl­idene]-13-(4-hydr­oxy-3-methoxy­phen­yl)-11-methyl-1,11-diaza­penta­cyclo­[12.3.1.0(2,10).0(3,8).0(10,14)]octa­deca-3(8),4,6-triene-9,15-dione